Israel secretly sent a team of Mossad and Shin Bet agents to Australia in 1986 to hunt for the nuclear whistleblower Mordechai Vanunu, an Israeli newspaper said yesterday.

According to the Haaretz article, published on the morning of Mr Vanunu's release from prison, the agents were unable to find him in Sydney but traced him to London "by studying passenger lists and border crossing information". The article cited information provided by a former top Mossad official who was involved in Mr Vanunu's eventual capture.

Because such information is normally confidential or classified, this raises the possibility that Australian citizens or security officials colluded in Israel's hunt for the man who was threatening to release details of its covert nuclear weapons program. Haaretz said that Israeli officials had considered assassinating Mr Vanunu but decided not to on the grounds that he was an Israeli.

Detected in London, he was lured to Rome by a female Mossad agent. There he was abducted, smuggled to Israel and tried in secret for espionage and treason.

Meanwhile, London's Sunday Times had already published information and photographs supplied by Mr Vanunu, a former technician at Israel's Dimona nuclear plant who had converted to Christianity.

Based on the photographs, Western experts deduced that Israel had produced between 100 and 400 nuclear weapons. With tacit approval from Western governments, Israel has always refused to confirm or deny its possession of weapons of mass destruction, saying only that it will not be the first country to introduce such weapons into the Middle East conflict.

While the authorities have sought to justify the continuing restrictions on Mr Vanunu's rights in terms of national security, the Labour Party leader, Shimon Peres, defended them as "justice" for a man who had "violated norms and betrayed his country".

Mr Peres, the founder of Israel's covert nuclear program and the prime minister who ordered Mr Vanunu's abduction from Rome, later won the Nobel Peace Prize for his work on the failed Oslo peace accords.

The Justice Minister, Tommy Lapid, leader of the liberal Shinui Party, compared Mr Vanunu to William Joyce, the British collaborator known as Lord Haw-Haw, who hanged for making propaganda broadcasts for the Nazis during World War II.

Hatred of Mr Vanunu was further stoked on the eve of his release when Israeli security agents broke their own restrictions by releasing to the media a tape of a recent interrogation. In the tape, which Mr Vanunu says was made under false pretences, he said he did not believe there should be a state just for Jews and that the Dimona nuclear plant should be destroyed.

The Defence Ministry has justified its continuing confinement of Mr Vanunu by saying he still has nuclear secrets that he can reveal to the world.